Recent changes in diesel fuels and diesel fuel additives have resulted in new injector performance concerns with deposits, including a new type of deposit not experienced with older diesel fuel formulations. The injector performance concerns run across all segments; on-road fleets, mining equipment, farming equipment, railroad and inland marine engines.
Vehicle operators, fuel marketers, and engine manufacturers are now seeing deposits forming on the internal parts of fuel injectors. If left untreated, these deposits may lead to significant power loss, reduced fuel economy, and, in extreme cases, increased downtime and higher maintenance costs due to premature replacement of “stuck injectors.” The new deposits are believed to be a result of certain common corrosion inhibitors, biofuel components and acidic friction modifier, or other carboxylic components used in the fuel reacting with trace amounts of transition metals, alkali metal and alkaline earth metals causing salts that are less soluble in ultra low sulfur diesel (ULSD) fuels than in the higher sulfur fuels of the past. When such salts are present in fuel that is used in a High Pressure Common Rail (HPCR) engine design, the salts may tend to deposit in the very tight tolerance areas of the injectors. Such deposits may lead to poor fuel injection, which in turn may lead to lost power, lost fuel economy, rough running engines, and eventually excessive vehicle downtime and maintenance expense.
ULSD now represents about 79% of all distillate fuel supplied in the United States. Also, the Renewable Fuel Standard minimum for biodiesel was raised to 1 billion gallons in 2012. There are indications that the amount of biodiesel required to be used in fuel will be even higher in the future. Accordingly, the changing fuel slate continues to move toward more ULSD (with less solubility for salts that can form) and more biodiesel in the marketplace (another potential source of deposit causing materials in the fuel system).
In accordance with the disclosure, exemplary embodiments provide a method cleaning up internal components of a fuel injector for a diesel engine. The method includes operating a fuel injected diesel engine on a fuel composition that contains a major amount of diesel fuel having a sulfur content of 50 ppm by weight or less and from about 5 to about 500 ppm by weight of a reaction product derived from (a) a hydrocarbyl substituted dicarboxylic acid, anhydride, or ester and (b) an amine compound or salt thereof of the formula
wherein R is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 15 carbon atoms, and R1 is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 20 carbon atoms. The reaction product is characterized by an FTIR spectrum having a peak intensity in a region of from about 1630 cm−1 to about 1645 cm−1 that ranges from about 5 to about 45% of peak intensities of other peaks in a region of from about 1500 cm−1 to about 1800 cm−1.
Another embodiment of the disclosure provides a method for reducing an amount of salt deposits on internal components of a fuel injector for a fuel injected diesel engine. The method includes operating the diesel engine on a fuel composition that contains a major amount of fuel and a minor amount of a reaction product derived from (a) a hydrocarbyl substituted dicarboxylic acid, anhydride, or ester and (b) an amine compound or salt thereof of the formula
wherein R is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 15 carbon atoms, and R1 is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 20 carbon atoms. The reaction product contains less than one equivalent of an amino triazole group per molecule of reaction product.
A further embodiment of the disclosure provides a method for preventing plugging of a fuel filter for fuel injectors of a fuel injected diesel engine. The method includes providing a major amount of fuel and a minor amount of a reaction product derived from (a) a hydrocarbyl substituted dicarboxylic acid, anhydride, or ester and (b) an amine compound or salt thereof of the formula
wherein R is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 15 carbon atoms, and R1 is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 20 carbon atoms. The reaction product is characterized by an FTIR spectrum having a peak intensity in a region of from about 1630 cm−1 to about 1645 cm−1 that ranges from about 5 to about 45% of peak intensities of other peaks in a region of from about 1500 cm−1 to about 1800 cm−1, and wherein the reaction product contains less than one equivalent of an amino triazole group per molecule of reaction product.
An advantage of the fuel additive described herein is that the additive may not only reduce the amount of internal deposits forming on direct and/or indirect diesel fuel injectors, but the additive may also be effective to clean up dirty fuel injectors and may prevent the plugging of fuel filters in the fuel supply to the fuel injectors.
Additional embodiments and advantages of the disclosure may be set forth in part in the detailed description which follows, and/or may be learned by practice of the disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.